The present invention relates to an electrical direct-current contact unit, and more particularly to a moveable contact for use in a direct-current, high-capacity circuit breaker.
German Pat. No. 1,202,378 discloses a contact bridge assembly consisting of a plate with electric arc horns which are electrically connected with each other by a bow-shaped electric arc control bracket. Circuit breakers of this type can only be used up to specified rated currents because the cross sectional area of the contact bridge is limited and its heat conductivity is relatively poor. According to German Offenlegungsschrift No. 1,640,262, a contact bridge is constructed in a U-shape and each leg of the bridge has one contact at its end. The current path forms a loop which reinforces the magnetic quenching of the electric arc. The contact bridge is nevertheless not very massive and features a small cross sectional area.
It is an object of the present invention to overcome the disadvantages of these well-known devices and to produce an electrical direct-current contact unit, and more particularly, a moveable contact for a direct-current, high-capacity circuit breaker, which is sufficiently mechanically stable, features a large cross sectional area, possesses good thermal conductivity and forms a current loop during opening of the contacts to thereby cause a magnetic self-quenching of the electric arc.